Method of reproducing from storage medium storing interactive graphics stream activated in reponse to user&#39;s command

ABSTRACT

A method of reproducing from a storage medium video data and graphics data for displaying a menu screen. The method includes: decoding graphics data; and outputting, on the basis of the decoded graphics data, the decoded graphics data when an activation command is generated by a user or displaying the decoded graphics data at a designated time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application Nos.2004-2716 and 2004-22042, respectively filed on Jan. 14, 2004 and Mar.31, 2004, in the Korean Intellectual Property Office, the disclosures ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to reproduction of a multimedia image, andmore particularly, to method of reproducing from a storage mediumstoring an interactive graphics stream displayed in response to a user'scommand.

2. Description of Related Art

To reproduce a multimedia image, audio-visual (AV) data of themultimedia image, navigation data controlling reproduction of the AVdata, and system data including command information related to a titleof AV data to be initially reproduced when the storage medium isinserted in a reproducing apparatus are recorded in a storage medium.Other data can also be recorded in the storage medium. In particular,the AV data is recorded in the storage medium by multiplexing video,audio, subtitles, and a menu as a main stream.

FIG. 1 is a block diagram of general AV data recorded in a storagemedium.

Referring to FIG. 1, in a storage medium storing a multimedia image, avideo stream 102, an audio stream 104, a presentation graphic stream 106for providing a subtitle, and an interactive graphics stream 108 forproviding a menu screen are multiplexed (MUX) and recorded as a mainstream. Hereinafter, the multiplexed main stream is called AV data 110.

FIG. 2 is a block diagram of a general reproducing apparatus forreproducing AV data from a storage medium 200 in which the AV data 110is recorded.

Referring to FIG. 2, a reproducing apparatus for reproducing amultimedia image reads navigation data, as described above, and obtainscontrol information required for reproducing the AV data 110. Forexample, the control information includes a coding type of the AV data110, a bit rate, information indicating an area in which the AV data 110is recorded, and the type of data included in the AV data 110. Byreferring to the control information, a reading unit 210, ademultiplexer 220, video, presentation, interactive graphics, and audiodecoders 230, 240, 250, and 260, respectively, are controlled.

In detail, with concurrent reference to FIGS. 1 and 2, the reading unit210 reads multiplexed AV data 110 from a storage medium 200 using theinformation indicating the area in which the AV data 110 is recorded andtransmits the multiplexed AV data 110 to the demultiplexer 220. Thedemultiplexer 220 divides the received AV data 110 into the video stream102, the audio stream 104, the presentation graphic stream 106, and theinteractive graphics stream 108 and transmits the divided streams 102through 108 to the decoders 230 through 260, respectively. Each streamtransmitted to the respective decoder is decoded according to acorresponding data type and ready to be displayed on a screen at adesignated time. The decoded video stream 102, the presentation graphicstream 106, and/or the interactive graphics stream 108 are overlaid as asingle image using a blender 270. Finally, an image selected based on anoutput status set by a user is displayed on the screen. For example, anoutput status can be controlled based on a user's selection such as of asubtitle on/off status and a mute status, etc.

In particular, the interactive graphics decoder 250 receives theinteractive graphics stream 108 from the storage medium 200, decodes theinteractive graphics stream 108, and outputs a menu screen includingbuttons on the screen at a designated time. A user's selection can beinput by the user selecting a specific button on the output menu screen.That is, a user interactive function can be provided.

However, a conventional reproducing apparatus unconditionally outputs amenu screen at a designated time even if a user does not want to watchthe menu when reproducing multimedia such as a movie. If an undesiredmenu screen is displayed when viewing a movie, a user may beinconvenienced.

BRIEF SUMMARY

According to an aspect of the present invention, there is provided areproducing method of reproducing a storage medium storing video dataand graphics data for displaying a menu screen. The method includesdecoding graphics data, and on the basis of the decoded graphics data,outputting the decoded graphics data when an activation command isgenerated by the user or outputting the decoded graphics data at adesignated time.

According to another aspect of the present invention, there is provideda method of reproducing an interactive graphics stream from a storagemedium, including: reading an interactive graphics stream from thestorage medium; decoding the read interactive graphics stream;determining a type of the read interactive graphics stream, and blendingthe decoded interactive graphics stream with video data and one ofdisplaying the blended data at a designated time when the decodedinteractive graphics stream is a normal interactive graphics stream anddisplaying the blended data when an activation command is received whenthe decoded interactive graphics stream is an on-demand interactivegraphics stream.

Additional and/or other aspects and advantages of the present inventionwill be set forth in part in the description which follows and, in part,will be obvious from the description, or may be learned by practice ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a view of conventional AV data recorded in a storage medium;

FIG. 2 is a view of a conventional reproducing apparatus for reproducinga storage medium in which AV data is recorded;

FIG. 3 illustrates a configuration of an interactive graphics streamaccording to an embodiment of the present invention;

FIG. 4 illustrates an operation when a normal interactive graphicsstream is reproduced;

FIGS. 5A and 5B illustrate operations when an on-demand interactivegraphics stream is reproduced according to an embodiment of the presentinvention;

FIGS. 6 a through 6 c illustrate a method of discriminating an on-demandinteractive graphics stream according to an embodiment of the presentinvention from a normal interactive graphics stream;

FIG. 7 illustrates a method of discriminating an on-demand interactivegraphics stream according to another embodiment of the present inventionfrom a normal interactive graphics stream;

FIG. 8 illustrates a method of discriminating an on-demand interactivegraphics stream according to another embodiment of the present inventionfrom a normal interactive graphics stream;

FIG. 9 is a block diagram of a reproducing apparatus for reproducing anon-demand interactive graphics stream according to an embodiment of thepresent invention;

FIG. 10 is a block diagram of a reproducing apparatus for reproducing anon-demand interactive graphics stream according to another embodiment ofthe present invention;

FIGS. 11A-11D illustrate an interactive graphics streams included in AVdata according to an embodiment of the present invention;

FIG. 12 illustrates a configuration of a player status registerrecording information regarding an interactive graphics stream accordingto an embodiment of the present invention;

FIG. 13 illustrates a configuration of a player status registerrecording information regarding an interactive graphics stream accordingto another embodiment of the present invention;

FIG. 14 illustrates a process of handling a command for activating anon-demand interactive graphics stream generated by a user;

FIGS. 15A and 15B show display statuses according to values of adisp_flag flag for the configurations of player status registers shownin FIGS. 12 and 13, respectively;

FIG. 16 illustrates a system menu of a reproducing apparatus in whichmenu items for turning an output of an on-demand interactive graphicsstream on/off are defined;

FIG. 17 is a schematic diagram of a remote control including a buttonfor turning an output of an on-demand interactive graphics streamon/off;

FIG. 18 is a flowchart illustrating a method of reproducing a storagemedium on which an interactive graphics stream is recorded according toan embodiment of the present invention; and

FIG. 19 is a detailed flowchart illustrating the method of reproducing astorage medium on which an on-demand interactive graphics streamillustrated in FIG. 18 is recorded.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentinvention by referring to the figures.

As used in the present Specification, a normal interactive graphicsstream refers to a data stream which provides a menu screen at adesignated time. Also, as used in the present Specification, anon-demand interactive graphics stream refers to a data stream whichprovides a menus screen which is displayed only when a user desires.

FIG. 3 illustrates a configuration of an interactive graphics streamaccording to an embodiment of the present invention.

Referring to FIG. 3, an interactive graphics stream is divided intounits of epochs according to how a decoder operates. Information forreproducing a button on a menu screen including a plurality of buttonsis called an interactive graphics object. All interactive graphicsobjects included in an epoch are decoded and stored in an object bufferof an interactive graphics decoder, to be described later, and unlessdata of a subsequent epoch is input, the stored objects are maintained.Accordingly, in one epoch, the interactive graphics object does not haveto be decoded every time it is used, and the already decoded and storedinteractive graphics objects can be reused. However, when a subsequentepoch starts after one epoch is finished, all buffers of the decoder arereset, and all stored data disappears. Also, the amount of time afterwhich a buffer of the decoder is reset is defined as a specified time.

Display sets are defined as output units of the interactive graphicsobjects, as shown in FIG. 3. A display set indicates a set ofinteractive graphics objects displayed on a single screen, and one epochcan include at least one display set. There are three types of displaysets. The first is an epoch start (ES) display set indicating the startof an epoch, and includes all data for outputting an interactivegraphics such as interactive graphics configuration information requiredfor configuring the interactive graphics and object data used for abutton image. The second is an acquisition point (AP) display set thatcan exist after the ES display set and includes all information forconfiguring an interactive graphic to prepare for a situation such as auser's random search. The third is a normal state (NC) display setincluding data that must be changed among interactive graphics in aprevious display set, i.e., only data to be updated. As shown in FIG. 3,one epoch can include a plurality of display sets. The ES display setexists at an initial part of an epoch, and AP and NC display sets arelocated at subsequent positions. An ES display set is necessary for eachepoch, but the AP and NC display sets are optional.

Each display set includes a composition segment storing configurationinformation of an interactive graphics stream, a plurality of definitionsegments, each recording object data such as a real image of a buttondisplayed on a screen, and an end segment indicating the end of thedisplay set. The composition segment includes output finish timeinformation, button configuration information, and operation informationindicating how a reproducing apparatus responds to a user operation. Thecomposition segment can be realized with an interactive compositionsegment (ICS) data structure. The definition segment includes an objectdefinition segment (ODS) including object data having image informationof a button and a palette definition segment (PDS) including colorinformation adapted to the ODS.

Each segment in a single display set is recorded in a packetizedelementary stream (PES), which is a packet unit of an MPEG-2 transportstream (TS). A relevant display set is decoded at a decoding timeindicated by a decoding time stamp (DTS) included in the PES, and isdisplayed on a screen at a presentation time indicated by a presentationtime stamp (PTS). Also, an output finish time when the output of therelevant display set is complete is determined by a composition_time_outpts field value recorded in the ICS indicating a data structure of thecomposition segment.

Accordingly, the interactive graphics stream is displayed on the screenat a designated time indicated by the PTS, a user command is received,an operation is performed in response there to, and the interactivegraphics stream disappears from the screen at a designated output finishtime indicated by composition_time_out_pts. However, if the interactivegraphics stream is output using only a designated time, a menu screen isunconditionally output at the designated time even if the user does notwant it to. That is, the menu screen can be activated at a time otherthan when the user wants it to, not just when a user wants it to.

Therefore, according to an embodiment of the present invention, anon-demand interactive graphics stream activated by a user's command isdefined by expanding a function of the interactive graphics stream toperform a user interactive operation. To discriminate from the on-demandinteractive graphics stream defined in the present invention, theinteractive graphics stream output at a designated time is called anormal interactive graphics stream.

The normal interactive graphics stream is displayed on a screen at adesignated time and disappears at a later designated time. On the otherhand, the on-demand interactive graphics stream is displayed on a screenonly when an activation command is generated by a user after all data isdecoded and ready to be output, and performs a designated operation inresponse to an input from the user. That is, as in the normalinteractive graphics stream, in the on-demand interactive graphicsstream, interactive graphics objects such as buttons can first bedisplayed at a time designated by the PTS. However, in the on-demandinteractive graphics stream, the buttons are not displayed on thescreen, unless the user inputs a command to do so.

In the normal interactive graphics stream, the composition_time_out_ptsindicates a time when the buttons are no longer displayed on the screen.However, in the on-demand interactive graphics stream, thecomposition_time_out_pts indicates a time when data related to thebuttons is deleted from the buffer of the decoder. That is, even if abutton activation command is generated by the user after the outputfinish time, since the on-demand interactive graphics stream to beactivated does not exist any longer, the activation command from theuser is ignored.

FIGS. 4, 5A and 5B are drawings illustrating an operational differencebetween a normal interactive graphics stream (FIG. 4) and an on-demandinteractive graphics stream (FIGS. 5A and 5B) according to an embodimentof the present invention.

FIG. 4 illustrates an operation when a normal interactive graphicsstream is reproduced. Referring to FIG. 4, normal interactive graphicsstreams are multiplexed in AV data. Each decoded normal interactivegraphics stream is displayed on a screen according to a PTS included inan ICS of an ES display set. Here, a user can navigate or select buttonsdisplayed on the screen. According to a user command, an operationassigned a button is performed.

For example, when navigating a button, a state of the button is changedfrom a selected state to an unselected state, an output image of thebutton is changed so as to be suitable for the unselected state, andwhen the user selects a specific button, an operation according to anavigation command assigned to the specific button is performed. Also,when the command assigned to the specific button is a command to move toanother location of the AV data, even if an output finish time(composition_time_out_pts) of the normal interactive graphics stream hasnot been reached yet, the specific button disappears from the screen,and AV data indicated by the move command is displayed on the screen. Onthe other hand, when the command assigned to the specific button is notthe command to move to another location of the AV data, the commanddefined to the specific button is performed, an output state of eachbutton is maintained until the output finish time(composition_time_out_pts) is reached, and when the output finish time(composition_time_out_pts) is reached, the specific button disappearsfrom the screen. That is, a normal interactive graphics stream isdisplayed on a screen at a designated time, and when a designated outputfinish time is reached, the normal interactive graphics streamdisappears from the screen.

FIGS. 5A and 5B illustrate operations when an on-demand interactivegraphics stream is reproduced according to an embodiment of the presentinvention. (0030] Referring to FIG. 5A, on-demand interactive graphicsstreams are multiplexed in AV data. When an on-demand interactivegraphics stream is decoded, the on-demand interactive graphics stream isready to be activated. Even if the on-demand interactive graphics streamis ready to be activated, a relevant button is displayed on a screenonly if a user's command is generated, in which case, a user command canbe received. The relevant button displayed on the screen disappears fromthe screen when an output finish time (composition_time_out_pts) isreached. Also, all decoded data in a buffer of a decoder disappears whenthe output finish time is reached by setting an epoch to the outputfinish time. Therefore, a user's activation command received after theoutput finish time is ignored.

Referring to FIG. 5B, as with the normal interactive graphics streamshown in FIG. 4, an epoch can be defined to terminate before it reachesa subsequent ICS of an ES display set. In this case, since all relevantdata in a buffer of a decoder is deleted when the subsequent ICS of theES display set is reached, even if an output finish time(composition_time_out_pts) has been reached, the relevant data does nothave to be deleted from the decoder. However, even if an activationcommand of a menu is generated by a user after the output finish time isreached, a selected button is not reproduced by recognizing that a validinteractive display duration has ended. That is, a user's activationcommand received after the output finish time is ignored.

As described above, an on-demand interactive graphics stream and anormal interactive graphics stream have a similar data structure.However, a difference between the two streams is that the displaying ofa button on a screen is determined by a user's activation command in theon-demand interactive graphics stream and by a designated time in thenormal interactive graphics stream. That is, if only information fordiscriminating two types of interactive graphics streams is added, thesame data structure can be used for realizing the two types ofinteractive graphics streams.

Additional methods of discriminating the on-demand interactive graphicsstream from the normal interactive graphics stream are as follows:

First method: a method of discriminating the two streams by using asegment_type field of an ICS

Second method: a method of discriminating the two streams by adding anICS_type field to the ICS

Third method: a method of discriminating the two streams by defining anOn_demand_ICS structure as a new structure of the on-demand interactivegraphics stream.

FIGS. 6A through 6C illustrate a method (the first method) ofdiscriminating an on-demand interactive graphics stream according to anembodiment of the present invention from a normal interactive graphicsstream.

Referring to FIGS. 6A and 6B, a graphics_segment structure includes asegment_descriptor 602 which includes a segment_type field 604indicating a segment type. In FIG. 6C, segment types, which thesegment_type field 604 can indicate, are defined. In the first method,the segment_type field 604 can be defined such that a normal interactivegraphics stream type (Normal_ICS) 606 has a value 0×18 and an on-demandinteractive graphics stream type (On_demand_ICS) 607 has a value 0×19.That is, the first method discriminates the two types of interactivegraphics streams using the segment_type field 604 when the two types ofinteractive graphics streams have the same structure.

FIG. 7 illustrates a method (the second method) of discriminating anon-demand interactive graphics stream according to another embodiment ofthe present invention from a normal interactive graphics stream.

Referring to FIG. 7, on-demand and normal interactive graphics streamshave the same structure (interactive_composition_segment), and in thesecond method, the two types of interactive graphics streams arediscriminated using an ICS_type field 702. That is, the ICS_type fieldis defined so that, if a value of ICS_type is 0, ICS_type indicates anormal interactive graphics stream, and if a value of ICS_type is 1,ICS_type indicates an on-demand interactive graphics stream.

FIG. 8 illustrates a method (the third method) of discriminating anon-demand interactive graphics stream according to another embodiment ofthe present invention from a normal interactive graphics stream.

Referring to FIG. 8, a newly defined an On_demand_ICS structure isshown. Unlike the first and second methods in which the same structureis used, in the third method, a new structure of an on-demandinteractive graphics stream is defined.

Unlike a structure of a normal interactive graphics stream, theOn_demand_ICS structure, the new structure of the on-demand interactivegraphics stream defines pages to be configured operation by operationsuch as an initial menu page including an initial button informing auser that the on-demand interactive graphics stream is decoded and isready to be activated by the user and pages including buttons to bedisplayed after the on-demand interactive graphics stream is activatedby the user, i.e., a first menu page through an nth menu page. Each menupage to be displayed can include reproduction information of at leastone button to be displayed and command information indicating whatoperation will be performed if the button is selected.

On the basis of an on-demand interactive graphics stream according toembodiments of the present invention described above, a configuration ofa reproducing apparatus supporting the on-demand interactive graphicsstream according to an embodiment of the present invention will bedescribed.

FIGS. 9 and 10 are block diagrams of reproducing apparatuses forreproducing an on-demand interactive graphics stream according toembodiments of the present invention.

Referring to FIG. 9, an interactive graphics decoder 910 of areproducing apparatus according to an embodiment of the presentinvention is shown. AV data read from a storage medium is input to apacket identifier (PID) filter 902, and only an interactive graphicsstream is selectively transmitted to a transport buffer 904 and decodedby the interactive graphics decoder 910.

In the interactive graphics decoder 910, the interactive graphics streamis temporarily stored in a coding data buffer 912 and then transmittedto a stream graphics processor 914. After the interactive graphicsstream is decoded by the stream graphics processor 914, button imageobject data is transmitted to an object buffer 916, and buttonconfiguration information is transmitted to a composition buffer 918. Agraphics controller 920 builds output images for received object datawith reference to relevant configuration information and transmits thebuilt image to a graphics plane 930. That is, at the time identified bya PTS, an output start time of an interactive graphics stream, thegraphics controller 920 determines an image to be displayed on a screenand transmits the determined image from the object buffer 916 to thegraphics plane 930. The transmitted image is output with reference to acolor lookup table (CLUT) 932 according to color information included inthe relevant configuration information. Also, the graphics controller920 may change a button state according to a move or selection of abutton in response to a user command and adapt this result to a screenoutput.

Particularly, FIG. 9 shows a block diagram of a reproducing apparatusconfigured such that a normal interactive graphics stream and anon-demand interactive graphics stream use the same buffer memory. Sincethe two types of interactive graphics streams use the same buffer of thedecoder 910 as shown in FIG. 9, only one of the normal interactivegraphics stream and the on-demand interactive graphics stream can existin the buffer of the decoder 910 at a given time. That is, only one typeof interactive graphics stream can be processed at once.

FIG. 10 is a block diagram of a reproducing apparatus for reproducing anon-demand interactive graphics stream according to another embodiment ofthe present invention.

Referring to FIG. 10, a reproducing apparatus configured such that anormal interactive graphics stream and an on-demand interactive graphicsstream are stored in separate buffer memories is shown. That is, thenormal interactive graphics stream is stored in a normal ICS memory area1010, and the on-demand interactive graphics stream is stored in anon-demand ICS memory area 1020. Therefore, the two types of interactivegraphics streams can simultaneously exist in buffers. In this case, whena normal interactive graphics stream is input in a state where anon-demand interactive graphics stream exists in a buffer, or when anon-demand interactive graphics stream is input in a state where a normalinteractive graphics stream exists in a buffer, the buffer memory of adecoder does not have to be reset. However, when the two types ofinteractive graphics streams are simultaneously displayed on a screen,it may not be clear which object a user operation is related to, andadapting color information to a screen configuration can be problematic.Therefore, even though not shown in FIG. 10, the reproducing apparatuscan further include a control unit selecting the normal interactivegraphics stream or the on-demand interactive graphics stream to beoutput and the respective CULT block for the interactive graphicsstream.

FIG. 11 illustrates an interactive graphics stream included in AV dataaccording to an embodiment of the present invention.

Referring to FIG. 11, FIG. 11A shows a case where only on-demandinteractive graphics streams are recorded in single AV data. FIG. 11Bshows a case where only normal interactive graphics streams are recordedin single AV data. FIG. 11C shows a case where two types of interactivegraphics streams are mixed and recorded in single AV data. FIG. 11 Dshows a case where two types of interactive graphics streams are mixedand recorded in single AV data and on-demand interactive graphicsstreams are separated from the other AV data and recorded. Inparticular, referring to FIG. 11D, when the AV data is read from thebeginning, on-demand ICS data recorded at the beginning of the AV datais referred to. However, when the AV data is read from a middleposition, since only configuration information is recorded in the AVdata while object data of a real button image is separately recorded,the button is output using the separately recorded object data withreference to the configuration information recorded in the AV data. Inthis case, unnecessary data redundancy can be prevented by separatelyrecording the object data.

On the basis of the data configurations of an on-demand interactivegraphics stream and the configurations of a reproducing apparatusdescribed above, a process of outputting the on-demand interactivegraphics stream to a screen according to a user's activation commandwill be described.

FIGS. 12 and 13 illustrate configurations of player status registers forrecording information regarding an interactive graphics stream accordingto embodiments of the present invention.

Referring to FIG. 12, in a player status register (PSR), a number of aninteractive graphics stream being currently reproduced or an interactivegraphics stream to be reproduced later is recorded. In FIG. 12, thenumber is recorded in bit0-bit7 of a PSR 0. Therefore, even whenreproduction of a multimedia image is temporarily stopped and restarted,an interactive graphics stream that was being reproduced just before canbe reproduced again by referring to the PSR 0.

In a reproducing apparatus supporting both normal interactive graphicsstream and on-demand interactive graphics stream, it must be determinedwhether a stream number recorded in the PSR 0 is a number indicating thenormal interactive graphics stream or the on-demand interactive graphicsstream. Therefore, a reproducing apparatus according to an embodiment ofthe present invention includes an ICS_usage flag for determining whetheran interactive graphics stream number recorded in the PSR 0 is a numberindicating the normal interactive graphics stream or the on-demandinteractive graphics stream. In FIG. 12, the ICS_usage flag is recordedin bit30 of the PSR 0. That is, if a stream being currently reproducedis an on-demand interactive graphics stream, the ICS_usage flag is setto 1, and if the stream being currently reproduced is a normalinteractive graphics stream, the ICS_usage flag is set to 0.

Also, in an on-demand interactive graphics stream, a disp_flag flag isdefined to indicate whether the stream is to be displayed on a screen.In FIG. 12, the disp_flag flag is recorded in bit31 of the PSR 0. If thedisp_flag flag is set to 1, when an on-demand interactive graphicsstream is ready to be activated, the reproducing apparatus displays aninitial menu page on the screen to inform a user that the on-demandinteractive graphics stream is ready to be activated. If the disp_flagflag is set to 0, the reproducing apparatus does not display aninteractive graphics on the screen.

On the other hand, when the disp_flag flag is set to 0 and an on-demandinteractive graphics stream is ready to be activated, that is, when theon-demand interactive graphics stream is ready to be activated and theon-demand interactive graphics stream is not to be displayed on thescreen, there are two methods of processing the on-demand interactivegraphics stream. In the first method, the reproducing apparatus isconfigured such that the on-demand interactive graphics stream isactivated when an activation command is generated by a user. In thesecond method, the reproducing apparatus is configured such that theon-demand interactive graphics stream is not activated and the user'scommand is ignored when generated by the user.

FIG. 13 illustrates a configuration of a player status registerrecording information regarding an interactive graphics stream accordingto another embodiment of the present invention. Referring to FIG. 13, areproducing apparatus configured to record two types of interactivegraphics streams in separate PSRs is shown. That is, a case whereinformation regarding a normal interactive graphics stream is recordedin a PSR 0 and information regarding an on-demand interactive graphicsstream is recorded in a PSR 11 is shown.

If an ICS_type field indicates a normal interactive graphics stream,information regarding the normal interactive graphics stream is recordedin the PSR 0, and if the ICS_type field indicates an on-demandinteractive graphics stream, information regarding the on-demandinteractive graphics stream is separately recorded in the PSR 11.Accordingly, unlike the configuration shown in FIG. 12, an ICS_usageflag for determining an ICS type of an interactive graphics stream isnot required. However, in the PSR 11, it is required that a disp_flagflag indicating whether an initial menu page for informing a user thatan on-demand interactive graphics stream is ready to be activated isdisplayed on a screen, and the operation of the disp_flag flag is thesame as FIG. 12. In FIG. 13, the disp_flag flag is recorded in bit31 ofthe PSR 11.

FIG. 14 illustrates a process of handling a command for activating anon-demand interactive graphics stream generated by a user.

Referring to FIG. 14, when an activation command is generated by a user,a reproducing apparatus determines whether an on-demand interactivegraphics stream is ready to be activated in an interactive graphicsdecoder, and if the on-demand interactive graphics stream is ready to beactivated, the on-demand interactive graphics stream is displayed on ascreen, a focus is set to receive a user command, and a button selectionfrom the user is ready to be received. If the on-demand interactivegraphics stream is not ready to be activated, an activation command fromthe user is ignored, or a message informing the user that an on-demandinteractive graphics stream to be output does not exist is displayed onthe screen.

FIGS. 15A and 15B show display statuses according to values of adisp-flag flag for the configurations of player status registers shownin FIGS. 12 and 13, respectively.

Referring to FIG. 15A, when a disp_flag flag is set to 1, if anon-demand interactive graphics stream is decoded and ready to beactivated, an initial menu page is displayed on a screen informing auser that the on-demand interactive graphics stream is ready to beactivated. If an activation command for the on-demand interactivegraphics stream is generated by the user, a first menu page is displayedon the screen.

Referring to FIG. 15B, when the disp_flag flag is set to 0, the initialmenu page is not displayed on the screen even if the on-demandinteractive graphics stream is decoded and ready to be activated.However, when an activation command for the on-demand interactivegraphics stream is generated by the user, a reproducing apparatus can beconfigured so that the activation command is ignored or the first menupage is displayed on the screen.

FIG. 16 illustrates a system menu of a reproducing apparatus in whichmenu items for turning an output of an on-demand interactive graphicsstream on/off are defined. If a user sets an On-demand ICS Display itemon, a disp_flag flag of a status register storing information regardingthe on-demand interactive graphics stream, for example, the PSR 0 or thePSR 11 described above, is set to 1. On the other hand, if the user setsthe On-demand ICS Display item off, the reproducing apparatus sets thedisp_flag flag of the status register as 0. That is, the disp_flag flagcan be changed using a user interface, which is called the system menu.

FIG. 17 is a schematic diagram of a remote control including a buttonfor turning an output of an on-demand interactive graphics streamon/off. A user can set a disp_flag flag of a status register to 0 or 1by pushing a relevant button.

On the basis of the data configurations of an on-demand interactivegraphics stream and the configurations of a reproducing apparatusdescribed above, a reproducing method according to an embodiment of thepresent invention will now be described.

FIGS. 18 and 19 are flowcharts illustrating a method of reproducing astorage medium on which an interactive graphics stream is recordedaccording to an embodiment of the present invention.

Referring to FIG. 18, an interactive graphics stream is read from astorage medium storing normal interactive graphics streams, and/oron-demand interactive graphics streams, in operation 1802. The readinteractive graphics stream is checked in operation 1804. The type ofthe decoded interactive graphics stream is checked in operation 1806. Ifthe decoded interactive graphics stream is a normal interactive graphicsstream, the decoded interactive graphics stream is blended with videodata and displayed on a screen at a designated time in operation 1808.If the decoded interactive graphics stream is an on-demand interactivegraphics stream, the decoded interactive graphics stream is blended withthe video data and displayed on the screen only if an activation commandis generated by a user in operation 1810.

FIG. 19 is a detailed flowchart illustrating the process of reproducingthe on-demand interactive graphics stream illustrated in FIG. 18.

Docket No.: 1793.1505

Referring to FIG. 19, if the decoded interactive graphics stream is anon-demand interactive graphics stream, a disp_flag flag indicatingwhether the on-demand interactive graphics stream is to be displayed onthe screen is read from a player status register in operation 1902. If avalue of the disp_flag flag is 1 in operation 1904, an initial menu pageinforming the user that the on-demand interactive graphics stream isready to be activated is displayed on the screen in operation 1906. Ifthe user inputs an activation command when the output initial menu pageis displayed in operation 1908, a menu page demanding on the usercommand is displayed on the screen in operation 1910.

On the other hand, if the value of the disp_flag flag is 0 in operation1904, nothing is displayed on the screen, and even if an activationcommand is generated by the user in operation 1920, the activationcommand is ignored in operation 1922. Even though it is not shown inFIG. 19, if the value of the disp_flag flag is 0, nothing is displayedon the screen, and if an activation command is generated by the userusing a user interface such as a remote control, the initial menu pageis displayed on the screen.

By using an on-demand interactive graphics stream according to describedembodiments of the present invention, the on-demand interactive graphicsstream can be controlled so that it is displayed on and disappears froma screen at designated times or displayed on the screen only if a usergenerates a command.

According to the described embodiments of the present invention, aninteractive graphics such as a button can be controlled by using anon-demand interactive graphics stream so that the button is displayed ona screen when a user generates a command.

Also, an interactive graphics stream specialized for a relevant area canbe configured by configuring different on-demand interactive graphicsstreams for certain areas or chapters of AV data. For example, insteadof buttons performing fixed functions, information related toactors/actresses, properties, and shooting locations existing in certainareas included in multimedia images can be provided to a user.

Furthermore, the number of buttons on a remote control can be reduced byconfiguring functions corresponding to the buttons of the remote controlwith a menu driven method using an on-demand interactive graphicsstream.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A reproducing method of reproducing from a storage medium video dataand graphics data for displaying a menu screen, comprising: decodinggraphics data; and outputting, on the basis of the decoded graphicsdata, the decoded graphics data when an activation command is generatedby a user or displaying the decoded graphics data at a designated time.2. A method of reproducing an interactive graphics stream from a storagemedium, comprising: reading an interactive graphics stream from thestorage medium; decoding the read interactive graphics stream;determining a type of the read interactive graphics stream; and blendingthe decoded interactive graphics stream with video data and one ofdisplaying the blended data at a designated time when the decodedinteractive graphics stream is a normal interactive graphics stream anddisplaying the blended data when an activation command is received whenthe decoded interactive graphics stream is an on-demand interactivegraphics stream.
 3. The method of claim 2, wherein, when the decodedinteractive graphics stream is an on-demand interactive graphics stream,the blending includes: reading a disp_flag flag indicating whether theon-demand interactive graphics stream is to be displayed from a playerstatus register; displaying, when a value of the disp_flag flag is afirst value, an initial menu page indicating that the on-demandinteractive graphics stream is ready to be activated. displaying a menupage according to a user command, when an activation command is receivedduring display of the initial menu page; and ignoring an activationcommand when the value of the disp_flag flag is a second value differentfrom the first value.
 4. The method of claim 3, wherein, when anactivation command is received from a user interface such as a remotecontrol, the initial menu page is displayed.
 5. The method of claim 2,wherein the determining includes analyzing a segment_type field of anICS.
 6. The method of claim 5, wherein the segment_type field indicatesa segment type and is located in a segment_descriptor field.
 7. Themethod of claim 6, wherein the segment_type field is defined such that anormal interactive graphics stream type has a value 0×18 and anon-demand interactive graphics stream type has a value0×19.
 8. Themethod of claim 2, wherein the normal interactive graphics stream andthe on-demand interactive graphics stream have the same structure. 9.The method of claim 2, wherein the determining includes analyzing anICS_type field of the ICS.
 10. The method of claim 9, wherein theICS_type field is defined so that, when a value of ICS_type is a firstvalue, a normal interactive graphics stream is indicated, and when avalue of ICS_type is a second value different from the first, anon-demand interactive graphics stream is indicated.
 11. The method ofclaim 2, wherein the determining includes analyzing a structure of theinteractive graphics stream.
 12. The method of claim 11, wherein astructure of the normal interactive graphics stream and an on-demandinteractive graphics stream differ.
 13. The method of claim 12, whereinthe structure of the on-demand interactive graphics stream defines firstthrough nth menu pages.
 14. The method of claim 13, wherein at least oneof the menu pages is an initial menu page including an initial buttonindicating that the on-demand interactive graphics stream is decoded andis ready to be activated, and wherein another of the menu pages includesa button to be displayed after the on-demand interactive graphics streamis activated.